This invention relates to illuminated signs, and more particularly to a traveling light type of advertising display in which illuminated indicia are moved across a viewing surface.
Prior illuminated signs of the type which displays successive indicia, such as letters spelling out word messages, have required a multiplicity of electric light bulbs mounted on a large display panel and connected in an electric circuit which includes a tray of mercury and a multiplicity of electrical contacts arranged for selective contact with the mercury by means of an interposed elongated tape provided with holes arranged in patterns representing indicia to be displayed by illumination of selected ones of the light bulbs as the contacts extend through the tape holes and make electrical contact with the mercury. Signs of this type are much too large for practical portability and use in small places, and they require excessive electric power for operation. They cannot be used on a mobile support, such as an airplane, because of errors introduced by loss of electrical contact with the mercury upon tipping of the airplane and because of complete failure of the sign upon loss of the mercury as a result of severe tilting of the airplane. Further, operation of the system results in the generation of mercury vapors which represent a hazard to health.
Prior illuminated signs of the type which may be transported manually and used in confined spaces, employ a multiplicity of optic fibers arranged in a spaced-apart pattern at their outer ends and in a concentrated, spaced-apart pattern at their inner ends, the latter registering with holes in a rotary disc or cylinder for illumination by a source of light on the side of the disc or cylinder opposite the inner ends of the optic fibers. This type of sign imposes a severe restriction on the number of indicia capable of being displayed in a repetitive cycle, thereby correspondingly limiting their practical applications. Typical of this type of illuminated sign are those described in U.S. Pat. Nos. 2,507,909; 3,184,872; and 3,836,911.